The invention relates to drop-in or built-in cutting boards which are normally secured in an appropriately apertured portion of a countertop or other work surface.
One such system utilizes a glass-ceramic plate mounted in the countertop by means of a frame in the form of a T-shaped band secured about the periphery of the plate. The band has an outwardly projecting flange adapted to overlap the aperture and rest on the countertop, and a downwardly depending annular rim with a lower portion thereof having a channel for pivotally supporting an anchoring clip. Normally such anchoring clips have a centrally located latch which is adapted to mate with the channel and opposed free arms, with one such arm for engaging the rearward portion of the countertop and the other having a threaded aperture therein for receiving a set screw. As the set screw is advanced it engages a rearward portion of the cutting board and causes the anchoring clip to pivot about the latch, to urge the other free arm to engage the rear of the countertop and thus pull the T-band inwardly to thus secure the assembly in the countertop. The set screw also engages the rearward side of the glass-ceramic plate to secure it in the band and support it against loads applied on the front side.
It is known that vitreous materials (glass and glass-ceramics) may be manufactured in such a way that they exhibit a high modulus of rupture (MOR). It is also known that such materials tend to fail in tension, especially when point loaded. In the cutting board assembly just described, the upper or front surface thereof is subjected to compressive forces of the user which normally would not cause breakage. However, should the upper surface of the cutting board (sometimes hereinafter board) be subjected to an unreasonable excessive load, the rearward portion of the board is placed in tension by such load. Further, the set screws utilized for sensing the board in the countertop may result in point load sources about the periphery thereof, which tend to increase the tensile forces thereof. As set forth above, the set screws not only secure the board in the countertop, they also function to support any load imposed thereon and transmitted thereto at various contact points about the periphery. Excessive point loading, of course, which may occur from improper installation or unreasonable use, may raise the applied force to some value above the MOR of the material and thus cause failure.
It is also important to note that the described prior arrangement requires assembly at the installation site. That is, the frame and cutting board assembly are shipped separately and installed in the formed opening of the countertop. Anchoring clips are manually installed about the frame in a more or less random spacing. It should be clear that some set screws may be torqued down with more force than others, and thus, the countertop may be subject to irregular or uneven stresses. The above procedure is also rather time consuming, since the frame and cutting board are shipped unassembled. As the anchoring procedure is accomplished, someone or something must be used to hold the assembly in place until it is secured properly. This cumbersome procedure could result in checking of the virtreous cutting board thereby greatly reducing its strength.
The present invention solves the problems referred to above by providing a drop-in unit which readily supports itself in the apertured countertop prior to installation and which includes a backing member capable of sustaining relatively high and typically nonuniform forces exerted on the assembly.